At the start of this month, alt-fuel and efficiency enthusiasts gathered in Watkins Glen, New York for the 5th annual Green Grand Prix expo and fuel economy rally. I entered my modified 1998 Pontiac Firefly (Geo Metro) in the rally, and managed to score the top result of 99.7 mpg (US) (2.4 L/100 km / 119.7 mpg imperial) in a field of 25 vehicles - including hybrids, diesels ... and even a pair of Vespa scooters! How does one squeeze 99 mpg from an old Metro? Here's the recipe - mods & driving techniques - used for the event...

This winter, EcoModder member Mike Turner was looking for a way to give the motoring public more information about his 1992 Honda Civic CX, which he has extensively modified to improve aerodynamics and reduce fuel consumption. Initially, he posted the car's "stats" directly on its flank: coefficient of drag (0.17 est.), fuel economy (70 mpg US average), higher top speed (140 mph estimated), etc.

Well, you've probably heard of the term "unintended consequences" ... and if Mike hadn't before, he definitely knows it now! The writing on the car resulted in enough additional rubbernecking to cause traffic problems, making lane changes difficult for Mike, and causing cars in the passing lane to bunch up behind the gawkers/readers.

If ever there was a reason to stick a web address on a vehicle, this was it. So I offered to make Mike a web site so he could replace the stats on the side of the car with "Aerocivic.com". Now motorists who see the car have the opportunity to learn the details from the safety of their computer chairs, rather than while barrelling down the highway beside it.

How important is tire pressure to rolling resistance and fuel economy? Apparently important enough that it became an issue in the 2008 US presidential election: one party mocked the other for suggesting that Americans could displace a significant amount of oil demand by simply maintaining their tires at the correct pressure.

Of course anyone with a shred of interest in efficiency already knows that tire pressure is one of the basic first steps.

But it's one thing to read stats, and another to see the relationship demonstrated in real life. So last summer I set out to do a snapshot test of how far (or not) my car rolls down the same course at varying tire pressure levels.

Apparently people are hungry for quality information - real ways to save fuel that don't involve dubious gadgets pitched in infomercials, additives promoted with no scientific basis, or hare-brained schemes that occasionally gain traction on the Internet.

(...Updated Sept 26/08...) My very first car was a behemoth: a 1964 Pontiac Catalina with a massively thirsty 389 cubic inch engine. When I bought it to restore, there was a little notebook in the glove box the previous owner had used to track his fuel economy. I remember the row of exclamation marks beside his best ever fill of 19 mpg (US). Unfortunately, 14 or 15 mpg was the norm.

The big Cat is long gone, and I've come full circle back to Pontiac via the Firefly. But the badge on the hood is about the only thing the Flea has in common with the monster Catalina. Its little 3 cylinder engine doesn't have even 1/6th the displacement of the 389 V8!

Apparently I'm not the only one who has downsized into a thrifty car lately. With $4 gasoline in the US this summer, people were abandoning their guzzlers... and apparently their common sense by paying startlingly high prices for some 1 litre action.

There's no question that the biggest potential fuel saving modification is adjusting the nut behind the wheel.

At the end of 2006 I posted a retrospective that showed this. I compared the impact of all the mods I'd done to the car against changes in driving style. The mods were collectively worth about a 28% improvement in MPG. And the driving techniques? How about a whopping 38% boost.

The benefit of a modded vehicle is that it will get better efficiency regardless of the driver. The benefits of developing efficient driving techniques is they're free and portable - you can bring them to any vehicle you drive.

OK, so spring may not the best time to be talking about block heaters. Then again, the planet has two hemispheres, after all. So while it may be finally warming up here, somewhere somebody may be plugging in a block heater right now...

Plus, who says block heaters are only for sub-zero use? I use mine three seasons of the year. (And the only reason I don't use it regularly in the summer is because I'm lazy.) Toyota's hybrids (like the Prius) employ their thermos-like tanks to preserve coolant heat for efficiency gains whether January or July.

The question this post addresses is: how long should you plug in a block heater? In other words, what's the shortest time needed for the maximum temperature rise?

34 years ago this month, the March 1974 issue of Car and Driver magazine ran an article about DIY modifications to improve fuel economy. The article was a direct response to the 1973/74 oil crisis - which was when people in North America first started seriously talking about improving fuel efficiency to address issues of energy security and high fuel prices.

But the magazine did a lot more than just talk about efficiency. They grabbed the bull by the horns (okay, a Ford Pinto by the bumper) and actually did something about it. Their story, Project Car: Crisis-Fighter Pinto, outlined six simple, mostly aerodynamic modifications which actually saved gas.

Last time I wrote about Rick was to profile his modded-for-mileage 1993 Metro XFi hatchback. At the time, he had a lifetime average of 53 mpg (US) since buying the car, with a more or less "normal" driving style.

Almost a year later, a quick look at his gas log shows it's climbed to 60.5 mpg. Nice work! Unfortunately, the secret to his success may lie partly in Mother Nature's aggressive vehicle weight reduction program - the XFi has been rusting out from under him!

But there's a silver lining: Rick just picked up a lightly roasted 1991 Metro convertible for $150 and has launched the ambitious Convertible XFi Project. It's shaping up to be much more than just a powertrain swap.

When I originally set up this site, I made a decision not to include visitor comments with the articles, thinking it would create too much work. Instead, I invited e-mail and responses submitted through the feedback page.

Well, let me tell you something: MetroMPG.com visitors are a chatty bunch! Since day one, I've received & answered literally hundreds of messages ... and lately the rate has been increasing. (So much for saving work.)

So with that in mind, I recently conceded defeat. But in a good way - with the launch of Ecomodder.com, a brand spanking new discussion forum about efficiency modifications, eco-driving techniques and fuel economy in general.